VIII

Glossary

ball grid array (bga) - The ball grid array is package for integrated circuits. Instead of leads, it has a grid of pads to which are attached balls made from solder.
annular rings - The conductive material on the pad that surrounds the hole.
aspect ratio - The ratio between the thickness of the board and the size of the drilled hole before plating.
blind via - A via which connects an outer layer to one or more inner layers but not to the other outer layer.
buried via - A via which connects one or more inner layers, but not to an outer layer.
design for manufacturing (dfm) - The process of designing a functional and reliable PCB that is easy to manufacture.
dielectric constant - The ratio of the permittivity of a substance to the permittivity of free space.
electro-deposited (ed) copper - A type of copper used to produce rigid PCBs.
land - A land is the remaining conductive material that remains after etching.
pad - A pad is the remaining conductive material after etching. See also “Land” and “Trace”.
panelization - The method of placing two or more PCBs onto one panel, which allows multiple boards to be made at the same time, reducing cost.
polarity indicators - Indicate components that can be connected to a circuit only in one direction (e.g. polarized capacitors, diodes, & LEDs).
pth (plated through hole) - A hole in which electrical connection is made between external or internal layers or both, by the plating of metal on the wall of the hole.
reference designator - Reference designators identify components on a electrical schematic or on a PCB (e.g. R253, TP12)
resin - A high-temperature thermoplastic used with glass to manufacture multilayered printed circuit laminates.
rolled copper - A type of copper, made very thin by processing between heavy rollers, extensively used to produce flexible PCBs.
shadowing - The blocking of the solder wave from small components by larger components or through hole component pins.
soldermask - A coating of material used to protect or mask conductive traces or areas of a PCB against solder bridging.
solder side (bottom) - A term used to describe the soldered side of a PCB using through hole technology.
surface mount technology (smt) - The technology of assembling PCBs and hybrid circuits where components are mounted onto pads on the surface of the substrate.
test point - A via or a pad with its own reference designator for probing and testing the nodes on a PCB.
tooling holes - A general term used for holes or slots in PCBs or blank material to aid in the manufacturing process.
trace - A conductive path or line. See also “Land” and “Pad”.
via - A plated through hole used as a through connection for conductors from the component side to solder side of the board or an outer layer to an inner layer
wave solder - The soldering of an assembly by passing the surface mount components, mounted on the solder side of the board, over an adhesive and then over a molten wave of solder.